Set screw



B. F. JACOBS.

SET SCREW.

APPLICATION FILED AUG.4. 1921.

1A38,64& Patented Dec. 12, 1922.

IN VN TOR.

Patented Dec. l2, i922.

BENJ'AJEEIN F. JACOBS, 0F BOSTON, ABBACHUSETTS.

ear scam.

Application 111ml August t, 1921.

To all whom it 'ma. concern:

Be it known that BENJAMIN F. JAooBs, a citizen of the United States ofAmerica and resident of Boston, in the county of Suffolk and State ofMassachusetts, have invented a new and useful Improvement in Set Screws,of which the following is a specification, reference being had to theaccompanying sheet of drawing, forming part thereof.

My invention relates to set-screws and the like, and has for its objectto provide a set-screw with an automatic self-locln'ng means, whichnormally serves to anchor the set-screw in set position when driven homeand otherwise serves to free the set-screw when being backed out fromthe aforesaid set and anchored position.

Another object of my invention is to provide a self-lockin set-screwwith an independent projectlng purchase peg in the bottom thereof, whichis .so designed as to permit of its being frictionally held in workingrelation with the set-screw for couplin the peg therewith to form .aunit device therefrom.

Still another object of theinvention is to provide a peg tip set-screwwhich comrises the combination of a split screw member and a wedgingpeg, which in the first instance serves to radially expand or contractthe split section of said screw member, and in the second instanceserves to provide a purchasing element for the set-screw.

To accomplish the aforesaid objects, ll employ a split-screw memberwhich is designed with a central, longitudinal bore in the lower endthereof, said bore being countersunk to provide a flared or taperedsection at the entrance thereof, together with a peg or plug which isdesigned with a tapered head adapted to wedge and spread the splitsection of said screw member as the same is being driven home, and anexpanding stem section adapted to fit the bore of said screw member andfrictionally hold said peg secured thereto.

Other objects and advantages of the in vention will be gathered from thedescription following herein and considered in connection with theaccompanying drawing wherein the invention is shown embodied.

The terms employed herein are used in the generic and descriptive senseto designate the elements illustrated, and are therefore not intended asterms of limitation.

Serial No. @9376.

In order to illustrate my invention, but

without being limited thereto, I have shown an embodiment thereof in thesheet of drawing wherein:

Fig. 1 represents an elevational view of my type of peg-tip set-screw;Fig. 2 represents a sectional view show- 1n r the set-screw inoperation; th 1g.t 3 represlfnts a pvirt sectional view of e se -screw sowln t e e or In frictlonally held therein p g p g Fig. 4 represents anelevational view of the peg or plug removed from the set-screw; Fig. 5represents an enlarged sectional view of the pegend of the set-screw,showing the set-screw before being driven home andabout to make purchasewith the shaft; Fig. 6 represents a similar view to Fig. 5, but showsthe set-screw driven home;

F g. 7 represents a sectional view taken on line 77 on Fig. 3;

accompanying Fig. 8 represents a sectional view taken on line 8-8 onFig. 4;

end of the set-screw; and

Fig. 10 represents the same view as Fig. 9, but shows the peg removedfrom the screw member.

Like numerals refer to like parts throughout the several views of thedrawing.

The numeral 20 represents a machine screw which is more particularlyknown and referred to as a set-screw; it being under stood that while Ihave shown the same provided with a square-shaped wrench head mylnvention applies as well to all other shapes and types of set-screws.The working-end 21 of the set-screw 20 is split longitudinally, as theslot 22 indicates, which provides for a radial spread to the set-screw,as will be hereinafter more fully explained. 23 represents a centralbore or chamber which is provided longitudinally in the setscrew andwhich may be blind, as the drawing indicates, or may pass clear throughthe set-screw, according as may be desired. Said bore at the working endof the set-screw is countersunk to provide, the tapered 0r flared seatsection 24.

25 represents a peg or plu which is rovided with the purchasing ilead ortip 26. the flared or conical shoulder section 27, the stem 28 whichfits the bore 23 of the set-screw, and the expansion or clutchinelements 29. The conical shoulder section 2 of said peg or plug 25 ispreferably inclined at an angle approximating, but greater than, theangle of slope to the countersunk section 24 of the set-screw bore,asthe drawing indicates. I

30 represents a collar which is provided with the radial tapped hole 31for rece 1v1ng the set-screw 20 therein, as shown in Fig. 1;

the set-screw serving to securely couple said collar 30 with the shaft32.

Having thus described the parts, of my invention in detail, the same isemployed as follows: First, it will be noted that theszg is slidablyfitted in the chamber provi therefor in the screw member 20, said peg Ibeing held therein by means of the ex ansion or clutching elements 29which notionally expand against the walls of the bore 23 and hold the egcoupled with the screwmember against ropping out therefrom, as

mi ht otherwise be possible. v T %ith the peg thus coupled with thescrew member the 'two forma unit set-screw which may be emplodyedwherever set-screws are ordinarily use I i The peg serves as thepurchaslng element of the set-screw, as may be understood, for the head26 of the peg is forcibly'brought up against the shaft 32 as theset-screw 1s is held against accidental backing out, which is a mostcommon and troublesome occurrence with the ordinary types of set-screws.

Incidentally the employment of the peg or plug, as herein described,provides for a much'more effective purchasing-feature for the set-screwinasmuch as ',tl ie take-up between the peg and the screw member. whendriving the set-screw home, provides for a grip or purchase against theshaft which is not possibly attainable in the ordinary setscrew which isdesigned to bottom directly on the shaft. This bottoming of the screwmember directly on the shaft has its disadvantages and often isresponsible for upsetting the end of the set-screw, which in manyinstances makes it impossible to remove the set-screw fromv the membercarrying the same. Forcing a set-screw under such circumstances usuallyresults in the breaking off of the head of the set-screw and requiresboring or drilling out of the set-screw.

With my type of set-screw herein described, the occurrence of theupsetting fea- 'ture above referred to is impossible, and

thus one of the most objectionable features of the' common .types ofset-screws is elimi-.

nated. Then again it must be apparent that in removin my type ofset-screw the mere I 29 thereof will normally hold the peg coupled withthe screw member so that the setscrew, as a unit is always intact andready for service. e

It will thus be noted that the set-screw ma be designed to serve anypurpose for whlch set-screws are ordinarily intended; that any type ofhead may be employed in connection with the pegor plug; that theconstruction of the .WlthlIl described setscrew is simple and may beproduced at a very low cost; that said set-screw possesses featureswhich are not possibly included or attainable in the present types ofset-screws; and finally that said set-screw yields results which areboth beneficial and advantageous in the machinery line. Y

While the preferred embodiments of my invention have been described indetail, it will be understood that I do not wish to be limited to thearticular construction set forth, since various changes in the form,material, and in the details of construction may be resorted to withoutdeparting from the spirit and scope of the invention, or destroying anyof the advantages contained in the same, heretofore described anddefined in the subjoined claims.

Having thus described my invention in detail, what I claim as new is:

1. The combination of a split set-screw. having a central and flaredchamber in the working end thereof; and a peg slidably fitting saidchamber and adapted to wedgedly spread the split portion of theset-screw for radially expanding the same and provided with spring meansintegral therewith for frictionally holding said peg in coupled relationwith said set-screw.

2. The combination of a split set-screw having a longitudinal chambertherein provided with a countersunk seat section at the 'mouth thereof;and a peg having a purchas- I chamber of said set-screw to frictionallyhold said peg in coupled relation therewith.

3. The combination of a set-screw having a longitudinal split thereinanda longitudinal countersunk bore at the working end thereof, and a pegprovided with a projecting, purchasing head, a wedging shoulder adaptedto wedgedly engage with the countersunk bore of the set-screw forradially spreading the split section thereof, and a centering stemprovided with expansion elements adapted to frictionally engage the pegwith the set-screw for frictionally coupling the two together.

4. A set-screw peg having a purchasing head, a wedging shoulder, and acentering 10 stem provided with integral expansion elements adapted tofrictionally engage the peg with the set-screw.

In testimony whereof, I aflix my signature this thirtieth day of July,1921.

BENJAMIN F. JACOBS. Witness:

DAVID LIOHI'ENSTEIN.

